The changes driven by the R186S mutation are in line with the emerging role of ER proteostasis in kidney disease, as evidenced for intermediate‐effect size variants in UMOD (Olinger et al, 2022) and for mutations in MUC1 also associated with ADTKD (Dvela‐Levitt et al, 2019). Here, MUC1 is linked to autosomal dominant medullary cystic kidney disease with or without hyperuricemia.